An influenza pandemic represents one of the greatest acute infectious threats to human health. The 1918-1919 influenza pandemic caused an estimated 500,000 deaths in the United States, making it the most fatal event in all of US history. The spread of highly pathogenic avian influenza (HPAI) H5N1 influenza across Asia and now to the Middle East and northern Africa creates a substantial risk for a new pandemic to arise.
Natural variation as well as escape mutants suggests that continued evolution of the virus should impact the decision on which strain(s) should be used for passive and active immunization. Although a number of important epitope mapping and neutralization escape studies have been reported new neutralizing antibodies and related structural studies are needed to develop immunization strategies to develop a “universal vaccine” against a broad range of Group 1 influenza viruses. The challenges to developing a protective vaccine against Group 1 influenza are formidable and new approaches are needed to prevent and treat human infection by an ever changing enemy. There is a need to rapidly develop therapeutic strategies to elicit protective host's immunity, both passively and actively.